In the conventional manufacturing process of thin film solar cells, as shown in FIGS. 1A-1G, a first electrode layer 11, e.g., a layer of TCO film, is sputtered on the backlight surface 101 of the glass substrate, and further patterning is carried out on the first electrode layer 11 by laser patterning to expose a part of the backlight surface 101 through the patterned openings.
After the step of patterning the first electrode layer 11 is finished, a photoelectric conversion layer 12 such as silicon film, is sputtered by vacuum sputtering process on the first electrode layer 11 and a part of the backlight surface 101 exposed through the patterned openings. Sequentially, laser patterning is conducted on the photoelectric conversion layer 12 to expose a part of the first electrode layer 11 in the formed patterned openings. After the step of patterning the photoelectric conversion layer 12, a glistening second electrode layer 13 can be sputtered on the photoelectric conversion layer 12 and a part of the exposed first electrode layer 11 through the patterned openings by vacuum sputtering once more. Finally, laser patterning is performed on the second electrode layer 13 and the photoelectric conversion layer 12, so as to expose a part of the first electrode layer 11 through the patterned openings, and accomplish the process of manufacturing the thin film solar cell.
However, the vacuum sputtering process demands expensive equipments, substantially raising the manufacturing cost, causing the total cost of the thin film solar cells unable to be effectively reduced. In addition, a preferred temperature used in the art for thin film solar cells is not beyond 150° C. so as for the cells not to be damaged at high temperature, but most of current sputtering equipment is accompanied by operating temperature as high as 200° C., such that the entire yield of thin film product is directly affected. Also, presently most of the second electrode layers 13 are silver electrodes; however, the silver electrode is unable to avoid surface plasmon absorption effect and affects efficacy of glistening. Under such circumstances, the total power generation efficiency of the thin film solar cell is not quite acceptable.
Moreover, Taiwan Patent Application Publication No. 201119048A1 disclosed a technique of using conductive ink fillings as back electrode of thin film solar cells. However, since the size of the conductive ink fillings is designed ranging from 0.5 nm to 300 nm, serious problems such as high scattering loss and surface plasma loss are inevitable, and thus reflectivity is unable to be raised.